23 . (42 - x) = 23

          42 - x = 23 : 23

          42 - x = 1

                 x = 42 - 1

                 x = 41

23*(42-x)=23

42-x       =23:23

42-x       =1

    x       =42-1

   x        =41

23*(42-x)=23

(42-x)=23:23

(42-x)=1

x=42-1

x=41

\(23.\left(42-x\right)=23\)

<=>  \(42-x=1\)

<=>  \(x=41\)

Vậy...

hk tốt

^^

23.(42 – x) = 23

42 – x = 23: 23

42 – x = 1

x = 42 – 1

x = 41

Vậy x = 41

b) 23 . (42 – x) = 23

Vì 23 . 1 = 23

Nên 42 – x = 1

x = 42 -1

x = 41

Vậy x = 41

c) |x - 1| = 25%

\(\frac{x-23}{24}+\frac{x-23}{25}=\frac{x-23}{26}+\frac{x-23}{27}\)

\(\frac{x-23}{24}+\frac{x-23}{25}-\frac{x-23}{26}-\frac{x-23}{27}=0\)

\(\left(x-23\right)\left(\frac{1}{24}+\frac{1}{25}-\frac{1}{26}-\frac{1}{27}\right)=0\)

=> x-23=0

x=0+23

x=23. Vậy x=23

Chúc bạn học tốt!^_^

\(\frac{x-23}{24}+\frac{x-23}{25}=\frac{x-23}{26}+\frac{x-23}{27}\) 

=> \(\frac{x-23}{24}+\frac{x-23}{25}-\frac{x-23}{26}-\frac{x-23}{27}=0\)

=>( x-13)(\(\frac{1}{24}+\frac{1}{25}-\frac{1}{26}-\frac{1}{27}\) = 0

ta thấy 1/24>1/25>1/26>1/27 => 1/24+1/25 - 1/ 26 - 1/17 > 0

=> x -13 = -

=> x=13

mình làm bài này từ hồi lớp 6

Vì 23 + X + 1947 = 1947 + 23 + X nên X = 1747

a) 720: ( x - 17) = 12

             x-17       = 60

             x            = 77

b) (-7)^2 (-23+x) = (-49)(-23 + 13)

     14(-23+x)       = 490

          -23 + x    = 35

                  x      = 58

a)  1 3 + 2 3 : x = − 7

⇔ 2 3 : x = − 7 − 1 3 ⇔ 2 3 : x = − 22 3 ⇔ x = 2 3 : − 22 3 ⇔ x = − 1 11

b)  2 3 : x = 1 , 4 − 12 5

⇔ 2 3 : x = − 7 5 ⇔ x = 2 3 : − 7 5 ⇔ x = − 10 21

c)  4 , 5 − 2 x .1 4 7 = 11 14

⇔ 4 , 5 − 2 x = 11 14 : 11 7 ⇔ 9 2 − 2 x = 1 2 ⇔ 2 x = 4 ⇔ x = 2